Method of manufacturing rubber articles



C. E. BRADLEY. METHOD OFMANUFACTURING RUBBER ARTICLES. m ucmpn FILED APR-20," 191a. RENEWED JULY 15. I920.

1,367,731, mama FM, 1921.,

2 SHEETS-SHEET I.

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' C. E. BRADLEY.

METHOD OF MANUFACTURING RUBBER ARTICLES. APPLICATION FILED APILZ O, 1918- RENEWED JULY 15. 1920- 1,367,?31. I PatentedFeb. 8, 1921.

2 SHEETS-SHEET 2.

@Wmi iii ii o, o s q?! curre CHAR? .'S E. BRADLEY. D1? IVIGNTCLAIR, NELV JERSEY. ASSIGNOB TO THE GGODYEAR METALLIC RUBBER SHOE COMPANY.

A. CORPORATEON' 0F CONNECTICUT.

Specification of Letters Patent.

Patented Feb. 8., i921.

Application filed. April 20. 1918, Serial No. 2252.723. Renewed July 15, 1920. Serial No. 396,612.

To all cc 1 mm 1 m [13/ con (er n.

lie it known that. i. CHARLES E. llnuonnr, a citizen of the United States, residing at lllontclair. in the county of Essex and State of New Jersey, have invented certain new and useful lnnn'ovemcuts in Methods of llllanunicturing llubber Articles. of which fihc following" is a full, clear, and exact descri ption.

This invention relates to the method of manufacturing articles of rubber. and more particularly to the vulcanization step in the manufacture of rubber footwear. The object of the invention is to provide a method of treating the built up boots on a form or lash whereby the vulcanization may be effected by subjecting them tothc action of steam.

in my application filed August 3, 1917. Serial Number 18%,220, I disclosed a method of vulcanizing hollow articles upon hollow forms in such manner as to prevent spotting of the article by condensation of the steam thereon, which condensation is caused by the cold forms, the method comprising an initialcirculation of a heating medium Within the form while. maintaining the opposite side of the form free "from contact with the steam. and subsequently subjecting the opposite Sllli to steam at u vulcaniaing temperature while subjecting the interior of the. form and article to a lesser pressure.

By the .present invention 1 provide a method of utilizing steam as a vi'ilconizinpg medium in the manufacture of rubber boots and shoes and other articles which consists in treating the article by the application of steam applied directly to one side thereof simultaneously with its application by conduction to the opposite side thereof, .Wlllll. subjecting the side subject to treatment by cmiduction to lesser pressure.

By the present invention steam may be employed as a vulcanizing medium without danger of spotting of the article. hurthcn more the method reduces the time of curing, inasmuch as it enables the rulcanizino; medium to he applied simultaneously to both sides of the stock; and the method possesses further utility as will hcroinaiicr be pointed out.

in the accompanying" drawings have shown an apparatus suitable for carrying; out my invention. the some forming the subject limiter oi a separate application.

wiring in the drawings,

last.

lush from the finished boot.

Figure l is a sectional. elevation of a vulcanizing chamber with a boot-supporting rack-car therein.

Fig. 2 is a sectional elevation oi. a boot Fig. 3 is a perspective VlQW oi the two last n'iembers separated.

Fig. i is a transverse section through the last on the line l4l, Fig. 2.

In carrying out my method the boot is built up according "to the. usual practice upon a hollow last A having a separable toe member a to permit the removal of the The members A nil-do are connected together by means of a bolt 1, the bolt having a thumb piece 2, and. its lower end being threaded in a bracket l secured Within the too 0;. At the base of the last member A. is constructed a shallow tube or duct 5 which, when the two last members are assembled, is in. register with a similar tube or duct 5* constructed in the base of the member a. The bottom wall of theuluct, in each" case, is the sole or the last, and the said sole is formed with a number of perforations G "for communication. between the duct and the exterior of the sole. At the top of the lost, projects a tapered nipple 'l' at the end of a pipe 8 which extends through the last. and. into communication "with the duct 5, 5*. G911].- munication between the interior of last memher A and the interior of last member a is effected through a port 9, surrounding bolt 1, and a tight joint between the lost members at the point surrounding the said port is effected by n ioans of a heat-proof peel;- ing 10. The vuicanizing chamber .11 is in communication with a steam pipe 12, and is adapo ed to receive a rack-car, the rack of which. may be built up of a hollow piping which communicates with the nipples 13, each of which is mluptod to receive the tapered bushing T in the end of a lost. The hollow 100 pipingoi the rack is prm/idcd with a l'lQ/Xi blc connection 14. \jvhich is adapted to. be coupled to a pipe 15 for providing a. differential of pressures between the surface of the boot and the interior thereof will later 105 more fully app llu carrying: out l'he method as applied to rubber boots, the lusts upon which the un- Vulcauizcd boots one. built up are placed" upon the nipples 13 of the rack, the rack;

car is placed within the vulcanizing chamher 11, and the latter is sealed. Thereupon the air in the chamber may be withdrawn through suction pipe 12* and steam is in troduced through the pipe 12, the steam passing into direct contact with each boot, and simultaneously into the interior of each last, through the opening about bushing '7 and thence through port 9, so that the boot supported by the last will be subjected to heat applied directly to one side thereof and by conduction through the walls of the last to the opposite side thereof.

In carrying ou'. the vulcanization, I subject the interior of the article supported upon the last to a lesser pressure than that of the surrounding steam. This is effected by opening the valve 16 of pipe 15 whereby the interior of the article may be brought into communication with a lesser pressure through perforations (i, duct 5, 5*, tube 8 and bushing 7. But contrary to the usual method of vulcanizing under diiferential, the lesser pressure assists the vulcanizing action of steam within the last, inasmuch as the article will be caused to hug the walls of the last and thereby to receive the full effect of the heat by conduction.

By my method, the tendency of the sole of a rubber boot to resist vulcanization is overcome. It is common in the construction of such soles to introduce a layer of rag stock intermediate the inner and outer soles. This rag stock contains a large proportion of cot ton and forms aninsulator; therefore the filling piece resists the conduction of heat from the exterior of the sole to the inner sole. But in the present method the rag stock does not obstruct vulcanization of the sole, inasmuch as the heating medium is applied fi'oin the interior of the last to the inv ner sole by conduction through the metal.

Not only may steam be employed as the vulcanizing agent by means of the present method, without danger of spotting the article, but vulcanization may be effected in much shorter time than is possible by the use of any method heretofore employed.

Having thus described my invention,

what I claim as new and desire to protect by Letters Patent:

1. The method of vulcanizing articles containing rubber, which consists in treating the article by the application of a heating medium applied directly to one side thereof and through a heat conductor to the opposite side thereof, while subjecting the interior of the article to a lesser pressure independent of and simultaneously with the application of the heating medium through the heat conductor.

2. The method of vulcanizing articles containing rubber, which consists in treating the article by the application of a heating medium applied to opposite sides thereof While subjecting the article to a dilferential of pressure, the lesser pressure being si jected independently of and simultaneously with the application of the heating medium to the opposite sides of the article.

3. The method of vulcanizing articles containing rubber, which consists in treating the article by the application of a heating medium applied simultaneously at opposite sides thereof, and at one side by conduction through a support therefor, while subjecting the article to a dilierential of pressure. the lesser pressure being subjected, independently of and simultaneously with the application of the heating medium ,applied by conduction.

4. The method of vulcanizing articles containing rubber, which consists in treating the article by the application of steam applied directly upon one side thereof and upon a support "for and thence by the heat of conduction to the opposite side of said article, While subjecting the article to a differential of pressure, the lesser pressure being subjected independently of and simultaneously with the application. of the heating medium applied by conduction.

Sigr; ed at New York, county of it ew Yorlr and State of New York, this 8th day of April, 1918.

CHARLES E, BRADLEY. 

